The present invention concerns a semiconductor device and a method of manufacturing the semiconductor device and it particularly relates to a semiconductor device including two types of transistors having characteristics different from each other and a method of manufacturing the semiconductor device.
Some semiconductor devices include two or more types of transistors having characteristics different from each other. For example, a semiconductor having both memory and logic circuits mounted on one identical semiconductor chip includes transistors for reading and writing memory and transistors forming a logic circuit. Decrease in leak current is required for the former type transistor and compatibility of high speed operation and low power consumption is required for the latter type transistor. In such a case, the two types of transistors may be sometimes different from each other with respect to the partial structure. For example, Japanese Unexamined Patent Application Publication No. 2011-66391 describes that the width of a side wall is different between a transistor for memory and a transistor for logic circuit.
Further, Japanese Unexamined Patent Application Publication Nos. 2010-67785 and 2010-171086 describe that an offset spacer film has a dual layered structure. Further, Japanese Unexamined Patent Application Publication No. 2011-3710 describes that an offset spacer film is removed from a region that serves as a source and a drain and a silicon layer is grown epitaxially over the regions in transistors for which refinement is required as a DRAM.